In each of electronic devices such as personal computers (PCs), smartphones, and car navigation systems, a central processing unit (CPU), a memory, and a communication interface for providing a communication function are installed in many cases. Such electronic devices communicate information with other electronic devices via wired or wireless networks such as local area networks (LANs) or wide area networks (WANs). The electronic devices are referred to as Internet of Things (IoT) devices in some cases.
A technique for using, as data storage, an IoT device connected to a network is being studied. For example, a system in which an IoT device used as data storage is set in a gateway (GW) device, and data output from the GW device or a sensor of the IoT device connected to the GW device is temporarily accumulated in the GW device is being studied.
Data accumulated in GW devices and the GW devices are managed by a data center connected to the GW devices via a network, for example. For example, IoT devices that have output data, information identifying GW devices accumulating the data, and directory information including key information to be used to search data and the like are managed by the data center. A user who wants to use specific data makes an inquiry to the data center, acquires directory information, references the acquired directory information, and detects a GW device accumulating the specific data.
A communication system in which a single master device and multiple slave devices that are connected to each other in series communicate with each other based on identification numbers has been proposed. In this communication system, a slave device automatically sets a self-identification number based on a numerical value, transmitted by a higher-level device, for setting the identification number and transmits the numerical value for setting the identification number to the next slave device based on the self-identification number. By this process, identification numbers are automatically set in all the slave devices.
Examples of the related art include Japanese Laid-open Patent Publication No. 2005-277978.